This invention relates generally to rotary inking devices of the type used in apparatus for applying printed indicia upon a moving line of articles and in particular, relates to the provision of a concentric spring loaded inking wheel being radially yieldable yet capable of maintaining concentricity after repeated use thereof.
In the reference copending application there was disclosed rotary inking wheel formed of an outer ring of inking material supported upon a hub or the like by a resiliently yieldable support structure consisting of at least one sleeve and a sponge-like ring formation. A support comprising a pair of concentric sleeves sandwiching a sponge-like annular member was described also. Thus, the inking wheel was provided with sufficient resilience to enable a constant pressure to be exerted upon the inking material without deterioration thereof. In other words, the mounting described afforded to the wheel a little "give" when impacted by the type carried by the imprinting wheel or by one of an intermediate train of transfer wheels.
The described earlier structure functioned well for a considerable duration. Notwithstanding its successful utilization, its adoption was limited since its useful life may be foreshortened due to its inability on recovery after radial movement, to maintain concentricity over sufficient duration of use to be fully satisfactory. The relatively foreshortened life expectancy may have been attributable to fatigue experienced by aging of the foam or sponge material comprising the sandwiched resilient material. It was found that the ring would give but after a relatively short time, would not return consistently to a condition where the desired concentricity would result. Even though protection was provided to avoid contamination by solvents and inks, the possibility of deterioration by exposure to such solvents and inks was one consideration limiting acceptability. Cost was a factor also as well as the number of parts and manner of manufacture of the support assembly, which raised costs of manufacture. Facility of assembly and disassembly was a factor also to be considered in evaluating acceptability to the industry.
Accordingly, it is desirable to improve the resiliently supported inking wheel of the earlier application by providing resilient means showing much reduced fatigue tendencies and which would be capable of maintaining concentricity of the inking wheel over a longer useful life, yet which would be easy to mount and to dismount on the hub of the wheel without loss of advantages which enhance the value of the previously described resiliently supported inking wheel.
Further, it would be of considerable advantage costwise if the above could be accomplished with elimination of the need to provide the molded or otherwise formed sleeves and resilient ring member sandwiched therebetween. All the above advantages would have to be provided without loss of effectiveness.